Ceramic matrix composite nozzle mounted with a strut and concepts thereof

ABSTRACT

A nozzle assembly is provided which is, in part, formed of a low coefficient of thermal expansion material. The assembly includes a nozzle fairing formed of the low coefficient of thermal expansion material and includes a metallic strut extending radially through the nozzle fairing. Load is transferred from the nozzle fairing to a static structure in either of two ways: first, the strut may receive the load directly and/or second, load may be transferred from the nozzle fairing to at least one of the inner and outer support rings. Further, the nozzle fairing and strut may allow for internal airflow for cooling.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. application Ser. No.14/574,472, filed on Dec. 18, 2014 and entitled Ceramic Matrix CompositeNozzle Mounted with a Strut and Concepts Thereof, which is herebyexpressly incorporated herein by reference in its entirety.

TECHNICAL FIELD

Present embodiments generally relate to a composite nozzle segmentassembly. More specifically, present embodiments relate to a compositenozzle segment assembly including a strut providing structural support.

BACKGROUND

A gas turbine engine includes a turbomachinery core having a highpressure compressor, combustor, and high pressure turbine (“HPT”) inserial flow relationship. The core is operable in a known manner togenerate a primary gas flow. The high pressure turbine includes annulararrays (“rows”) of stationary vanes or nozzles that direct the gasesexiting the combustor into rotating blades or buckets. Collectively onerow of nozzles and one row of blades make up a “stage”. Typically two ormore stages are used in serial flow relationship. These componentsoperate in an extremely high temperature environment, and must be cooledby air flow to ensure adequate service life.

HPT nozzles are often configured as an array of airfoil-shaped vanesextending between annular inner and outer bands which define the primaryflowpath through the nozzle.

Due to operating temperatures within the gas turbine engine, it isdesirable to utilize materials with low coefficient of thermalexpansion. For example, to operate effectively in such strenuoustemperature and pressure conditions, composite materials have beensuggested and, in particular for example, ceramic matrix composite (CMC)materials. These low coefficient of thermal expansion materials havehigher temperature capability than metallic parts. The higher operatingtemperatures within the engine result in higher engine efficiency.However, such ceramic matrix composite (CMC) have mechanical propertiesthat must be considered during the design and application of the CMC.CMC materials have relatively low tensile ductility or low strain tofailure when compared to metallic materials. Also, CMC materials have acoefficient of thermal expansion which differs significantly from metalalloys used as restraining supports or hangers for CMC type materials.Therefore, if a CMC component is restrained and cooled on one surfaceduring operation, stress concentrations can develop leading to failureof the segment.

Prior art nozzles formed of CMC materials have been attempted withlimited success. These nozzles must have constructions wherein loadcontrolled stresses are minimized. Attempts have been made to carrypressure loads acting on the CMC nozzle to support at the outer andinner bands of the nozzle. Generally, moments are created at the filletsof the inner and outer bands to accomplish this construction. Thisresults in high stresses at the interfaces of the vanes and bands,creating durability challenges for the CMC components.

It would be desirable to improve known nozzle assemblies in order toeliminate the creation of moment at the interface between the nozzle andassociated attachment features. It would further be desirable to providean assembly to support the CMC nozzle while limiting load on the part.It would further be desirable to allow for differential thermal growthbetween parts of differing material types.

The information included in this Background section of thespecification, including any references cited herein and any descriptionor discussion thereof, is included for technical reference purposes onlyand is not to be regarded subject matter by which the scope of theinvention is to be bound.

SUMMARY

A nozzle assembly is provided which is, in part, formed of a lowcoefficient of thermal expansion material. The assembly includes anozzle fairing formed of the low coefficient of thermal expansionmaterial and includes a metallic strut extending radially through thenozzle fairing. Load is transferred from the nozzle fairing to a staticstructure in either of two ways: first, the strut may receive the loaddirectly and/or second, load may be transferred from the nozzle fairingto at least one of the inner and outer support rings. Further, thenozzle fairing and strut may allow for internal airflow for cooling.

According to some embodiments, a nozzle segment assembly comprises anouter support ring and an inner support ring, a nozzle fairing formed ofa low coefficient of thermal expansion material having an outer band andan inner band, the nozzle fairing further having an vane extendingbetween the outer band and the inner band, a metallic strut extendingbetween the outer support ring and the inner support ring, the strutproviding for load transfer between at least one pair of said nozzlefairing and the strut or said nozzle fairing and at least one of aninner and outer support ring, the metallic strut extending through thenozzle fairing and allowing growth of the strut through the vane.

All of the above outlined features are to be understood as exemplaryonly and many more features and objectives of the structures and methodsmay be gleaned from the disclosure herein. Therefore, no limitinginterpretation of the summary is to be understood without furtherreading of the entire specification, claims and drawings includedherewith.

BRIEF DESCRIPTION OF THE ILLUSTRATIONS

The above-mentioned and other features and advantages of theseembodiments, and the manner of attaining them, will become more apparentand the embodiments will be better understood by reference to thefollowing description taken in conjunction with the accompanyingdrawings, wherein:

FIG. 1 side section view of an exemplary gas turbine engine;

FIG. 2 is a perspective view of an exemplary nozzle ring formed by aplurality of nozzle segment assemblies;

FIG. 3 is a perspective assembly view of the nozzle segment assemblyincluding strut extending through fairing;

FIG. 4 is an exploded assembly view of the nozzle segment assembly ofFIG. 3;

FIG. 5 is a schematic section view of various mounting options for thenozzle segment assemblies;

FIG. 6 is a partial section view of the nozzle assembly of FIG. 3;

FIG. 7 is a first section view of a nozzle and lug joint;

FIG. 8 is a second section view of a nozzle and pin joint;

FIG. 9 is a section view taken at line 9-9 of FIG. 5

FIG. 10 is a section view taken at line 10-10 of FIG. 5;

FIG. 11 is a perspective view of an alternative mounting structure forthe nozzle segment;

FIG. 12 is a perspective view of a seal box;

FIG. 13 is a section view of the exemplary seal box;

FIG. 14 is a perspective view of an exemplary strut;

FIG. 15 is a section view of the exemplary strut of FIG. 14; and,

FIG. 16 is a cross section of an alternative construction for a nozzleassembly.

DETAILED DESCRIPTION

It is to be understood that the depicted embodiments are not limited inapplication to the details of construction and the arrangement ofcomponents set forth in the following description or illustrated in thedrawings. The depicted embodiments are capable of other embodiments andof being practiced or of being carried out in various ways. Each exampleis provided by way of explanation, not limitation of the disclosedembodiments. In fact, it will be apparent to those skilled in the artthat various modifications and variations may be made in the presentembodiments without departing from the scope or spirit of thedisclosure. For instance, features illustrated or described as part ofone embodiment may be used with another embodiment to still yieldfurther embodiments. Thus it is intended that the present disclosurecovers such modifications and variations as come within the scope of theappended claims and their equivalents.

Embodiments of a nozzle segment assembly are depicted in FIGS. 1-16. Thenozzle segment assembly utilizes a material having a low coefficient ofthermal expansion, such as for example, ceramic matrix compositematerial. The assembly further comprises a strut formed of analternative material such as a metallic material which is capable ofcarrying higher loading than the low coefficient of thermal expansionmaterial. The strut carries loading through the nozzle segment assemblyand on to engine support hardware.

Also, it is to be understood that the phraseology and terminology usedherein is for the purpose of description and should not be regarded aslimiting. The use of “including,” “comprising,” or “having” andvariations thereof herein is meant to encompass the items listedthereafter and equivalents thereof as well as additional items. Unlesslimited otherwise, the terms “connected,” “coupled,” and “mounted,” andvariations thereof herein are used broadly and encompass direct andindirect connections, couplings, and mountings. In addition, the terms“connected” and “coupled” and variations thereof are not restricted tophysical or mechanical connections or couplings.

As used herein, the terms “axial” or “axially” refer to a dimensionalong a longitudinal axis of an engine. The term “forward” used inconjunction with “axial” or “axially” refers to moving in a directiontoward the engine inlet, or a component being relatively closer to theengine inlet as compared to another component. The term “aft” used inconjunction with “axial” or “axially” refers to moving in a directiontoward the rear of the engine.

As used herein, the terms “radial” or “radially” refer to a dimensionextending between a center longitudinal axis of the engine and an outerengine circumference.

All directional references (e.g., radial, axial, proximal, distal,upper, lower, upward, downward, left, right, lateral, front, back, top,bottom, above, below, vertical, horizontal, clockwise, counterclockwise)are only used for identification purposes to aid the reader'sunderstanding of the present invention, and do not create limitations,particularly as to the position, orientation, or use of the invention.Connection references (e.g., attached, coupled, connected, and joined)are to be construed broadly and may include intermediate members betweena collection of elements and relative movement between elements unlessotherwise indicated. As such, connection references do not necessarilyinfer that two elements are directly connected and in fixed relation toeach other. The exemplary drawings are for purposes of illustration onlyand the dimensions, positions, order and relative sizes reflected in thedrawings attached hereto may vary.

Referring initially to FIG. 1, a schematic side section view of a gasturbine engine 10 is shown. The function of the gas turbine engine 10 isto extract energy from high pressure and temperature combustion gasesand convert the energy into mechanical energy for work. The gas turbineengine 10 has an engine inlet end 12 wherein air enters the corepropulsor 13 which is defined generally by a compressor 14, a combustor16 and a multi-stage high pressure turbine 20 all located along anengine axis 26. Collectively, the core propulsor 13 provides thrust orpower during operation. The gas turbine engine 10 may be used foraviation, power generation, industrial, marine or the like.

In operation, air enters through the engine inlet end 12 of the gasturbine engine 10 and moves through at least one stage of compressionwhere the air pressure is increased and directed to the combustor 16.The compressed air is mixed with fuel and burned providing the hotcombustion gas which exits the combustor 16 toward the high pressureturbine 20. At the high pressure turbine 20, energy is extracted fromthe hot combustion gas causing rotation of turbine blades which in turncauses rotation of the shaft 24. The shaft 24 passes toward the front ofthe gas turbine engine 10 to continue rotation of the one or morecompressor 14 stages, a turbofan 18 or inlet fan blades, depending onthe turbine design. The turbofan 18 is connected by the shaft 28 to alow pressure turbine 21 and creates thrust for the gas turbine engine10. The low pressure turbine 21 may also be utilized to extract furtherenergy and power additional compressor stages.

With reference now to FIG. 2, a perspective view of a nozzle ring 29 isdepicted. The nozzle ring 29 may be located within the high pressureturbine 20 and/or low pressure turbine 21 (FIG. 1). The nozzle ring 29is formed of one or more nozzle segment assemblies 30. The nozzlesegment assemblies 30 direct the combustion gases downstream through asubsequent row of rotor blades (not shown) extending radially outwardlyfrom a supporting rotor 23 (FIG. 5). The nozzle ring 29 and plurality ofnozzle segment assemblies 30 defining the nozzle ring 29 aid in energyextraction by the rotor 23 (FIG. 5). Additionally, nozzles may beutilized in the compressor 14 which may be either of a high pressure orlow pressure compressor. The nozzle ring 29 includes an inner band 52and an outer band 54 and a plurality of struts 70 (FIG. 3) extendingthrough nozzle fairings 50. The inner and outer bands 52, 54 extend 360degrees defining the nozzle ring 29 about the engine axis 26 (FIG. 1).

The nozzle ring 29 is formed of a plurality of nozzle segment assemblies30 each of which includes an inner support ring 40, at least one nozzlefairing 50 and a hanger or outer support ring 60. Extending through atleast one nozzle fairing 50 is a strut 70 (FIG. 3). The strut 70 carriesload from the radially inward side of the nozzle segment assembly 30 atthe inner support ring 40 to the radially outward side at the outersupport ring 60 where load is transferred to a static structure 15 andmechanically supports the nozzle fairing 50. The strut 70 may beconnected to at least one of the inner support ring 40 and the outersupport ring in a variety of manners described herein including bybolting, fastening, capturing, combinations thereof and being integrallyformed.

Referring now to FIG. 3, a perspective view of an exemplary nozzlesegment assembly 30 is depicted. The nozzle segment assembly 30 is shownhaving a forward end at the right side of the figure and an aft endtoward the left side of the figure. The nozzle segment assembly 30 islocated between an upstream rotating turbine blade and a downstreamrotating turbine blade. The nozzle segment assembly 30 receivescombustion gas flow from upstream rotating turbine blades (not shown).The flow of combustion gas is turned by the nozzle segment assembly 30in order to increase work output at the downstream turbine blades (notshown).

Starting at the lower end of the nozzle segment assembly 30, the innersupport ring 40 extends circumferentially defining a portion of thenozzle segment assembly 30. The inner support ring 40 also extendsaxially defining a lower end of the segment of nozzle segment assembly30. The inner support ring 40 includes a lowermost surface 42 whichextends circumferentially and axially and the radially upwardlyextending surface 44 wherein a plurality of cooling holes are disposed.Angel wings may extend at forward and aft ends of the inner support ring40.

Disposed above the inner support ring 40 is the at least one fairing 50.The fairing 50 may be of the single vane type, generally known as a“singlet” or may be of the double vane type generally known as a“doublet”. These are merely exemplary as additional numbers of vanes maybe utilized in the nozzle segment assembly 30. The fairing 50 includesan inner band 52, an outer band 54 and at least one vane 56 extendingbetween the inner and outer bands 52, 54. The upper surface of the innerband 52 provides one flow surface for combustion gas. The lower surfaceof the outer band 54 provides an opposite flow surface for thecombustion gas. These surfaces define boundaries for flow of combustiongas through the nozzle segment assembly 30 with the vane 56 extendingtherebetween.

Disposed above the fairing 50 is the outer support ring 60 whichconnects the nozzle segment assembly 30 to a static structure 15. Theouter support ring 60 also extends circumferentially and axially betweena forward end 64 and an aft end 62. The outer support ring 60 furthercaptures the fairing 50 on the strut 70 between the outer support ring60 and the inner support ring 40. The strut 70 is fastened to the outersupport ring 60 and connected to the inner support ring 40 to transferload through the nozzle segment assembly 30. The fairing 50 ispositioned to float on the strut 70 and is captured between the outersupport ring 60 and inner support ring 40.

Referring now to FIG. 4, an exploded perspective view of the nozzlesegment assembly 30 is depicted. The inner support ring 40 includes theradially lower surface 42 and the radially outwardly extending uppersurface 44, extending from the forward end of the lower surface 42.Disposed through the upper surface 44 are a plurality of rotor purgefeed holes 46 which receive cooling air through the nozzle segmentassembly 30 and feeds out through the inner support ring 40. The feedholes 46 are in flow communication with circular collars 48, 49positioned on the inward surface 42 of the inner support ring 40. Thefeed holes 46 allow air to exit the inner support ring 40 in either orboth of a circumferential or axial direction. The collars 48, 49 receivethe strut 70 providing engagement with the inner support ring 40 and maybe fastened, according to one embodiment, through a slip-fit pinconnection capturing the strut 70 in the inner support ring 40. A secondportion 45 (FIG. 12) is positioned between the upper edge of the collars48, 49 and the upper surface 44 creating a flow cavity between collars48, 49 and the rotor purge feed holes 46. The lower surface 42 of theinner support ring 40 may include a honeycomb layer as known to oneskilled in the art.

Positioned above the inner support ring 40 are fairings 50 including theinner band 52, the outer band 54 and the vane 56. The interior of thevane 56 is at least partially hollow defining a cooling flowpath 58. Thevane 56 may include a plurality of film holes 59 along an outer surfaceof the vane to provide cooling for the vane 56. For example, the vane 56may include a plurality of film holes 59 along the trailing edge 57 inorder to cool this area of the vane 56 where hotspots may form. Otherlocations of the vane 56 may further comprise cooling film holes inorder to provide a desirable operating temperature for the vane 56.

The cooling flowpath 58 further comprises a secondary function which isto receive the strut 70 therein. When assembled, the strut 70 extendsdownwardly through the outer band 54, the vane 56 in the inner band 52so that a lower end of the strut 70 engages the inner support ring 40.According to this embodiment, the strut 70 is positioned within thecollars 48, 49 and may be connected in a variety of manners including,but not limited to, a slip-fit pin connection. Further, although asingle strut 70 is shown, additional struts may be utilized by each ofthe vanes 56. Thus in the exemplary embodiment, where nozzle segmentassembly 30 is shown with a fairing 50 having two vanes 56, two struts70 would be utilized in this exemplary embodiment.

The outer support ring 60 is positioned on the radially outward side ofthe upper band 54. The outer support ring 60 includes a plurality offastening apertures 66 and a cooling flowpath 68. Alternatively,fastening apertures 66 could extend from a flange 74 and be fastened bynuts or like fasteners at the outer support ring 60.

The cooling flowpath 58 of the fairings 50 is in flow communication withthe flowpath 68 of the outer support ring 60. Cooling air is capable ofmoving through the outer support ring 60 and downwardly through thestrut 70 to cool the vanes 56 to move further radially inwardly to theinner support ring 40.

The strut 70 is positioned downwardly through the fairing 50 and iscaptured in this position by outer support ring 60 and inner supportring 40. The plurality of fastening apertures 66 align with fasteningholes 72 disposed in the flange 74 of the strut 70 to connect thesestructures. The flange 74 is positioned at an upper end of the strut 70and a seal box interface 76 is located at a lower end of the strut 70. Afastener (not shown) may extend through the outer support ring 60 andthe flange 74. Extending between the flange 74 and the seal boxinterface 76, the strut 70 is shaped to match the shape of flowpath 58.In the exemplary embodiment, the strut 70 is shaped having anairfoil-like profile to fit within the similarly shaped cooling flowpath58. However, various alternate shapes may be utilized. At a trailingedge of the strut 70 are a plurality of cooling holes 79 which are inflow communication with a cooling path 78. The cooling path 78 receivesflow through the outer support ring 60 at cooling flowpath 68 whichenters the strut 70 and either passes through the cooling holes 79 orcontinues downwardly to the seal box interface 76 for dispersion throughthe inner support ring 40. Additionally, the strut 70 may includecooling holes 86 which provide cooling air to the vanes 56. One skilledin the art will understand that at least the flowpaths 58, 68, 78 andcollars 48, 49 also define cavities through the nozzle assembly 30allowing cooling air to move there through when assembled.

The strut 70 further comprises a plurality of load bearing pads 80 nearan upper end and beneath the flange 74. The load bearing pads 80 areprimarily located on the side of the strut 70 corresponding to thepressure side of the vanes 56. Similarly, load bearing pads 82 arelocated at a lower end above the seal box interface 76. The pads 80, 82locate the fairing 50 properly unto the strut 70. During operation, thepressure side of the vane creates a lateral and tangential load on thefairings 50 and the pads 80, 82 transfer the load to the strut 70,thereby limiting load application on the CMC fairing structure 50. Thepads 80, 82 provide a way to engage the strut 70 and fairing 50 whilelimiting tangential load transferred to the fairing 50. Alternativelystated, the nozzle segment assembly 30 allows for load transfer throughthe strut 70 with minimal stress on the fairing 50. In this nozzlesegment assembly 30, the fairing 50 may float radially along the strut70 between the inner support ring 40 and outer support ring 60. Despitethe differing materials of the fairing 50 and strut 70, the parts maygrow at different rates without damaging the fairing 50.

The strut 70 is metallic and may be cast, machined or some combinationthereof. The strut 70 is formed of a stronger material than the fairing50. The remaining portions of the nozzle segment assembly 30 may beformed of some low coefficient of thermal expansion material, includingbut not limited to CMC.

Referring now to FIG. 5, a side section view of an exemplary nozzlesegment assembly 30 is depicted with schematic connections for purposeof description. The nozzle segment assembly 30 may be connected to astatic structure 15 of the gas turbine engine 10, for example the enginecasing. The nozzle segment assembly 30 may be mounted in a cantileveredfashion or alternatively hung from the outer support ring 60. Forexample, a cantilevered connection 31 may be at an upper end at one ofthe axially forward end or axially aft end of each nozzle segmentassembly 30. Still further, the nozzle segment assembly 30 may becantilevered from a lower mount or from an upper mount as in thedepicted configuration. As used herein, the term “cantilevered” meanssupported at one end in either the radial or axial direction. Therefore,the inner support ring may be cantilevered from the outer support ring.Alternatively, the outer support ring may be cantilevered from the innersupport ring. This may also include alone or in combination support atone or both axial ends. Also, both support rings may be supported sothat neither is cantilevered.

Alternatively, the nozzle segment assembly 30 may be supported at theouter support ring 60 at both of the forward and aft ends at supports33. Still further, static structures 15 may be located at the radiallyinward end of the nozzle segment assembly 30, for example near the innersupport ring 40 (FIG. 3), in order to provide support at a radiallyinward location. In these arrangements, the nozzle segment assembly 30is supported from a static structure 15, for example an engine casing,which is radially outward of the nozzle segment assembly 30.Alternatively, or in addition, static structure 15 may extend to aposition radially inward of the nozzle segment assembly 30.Additionally, the nozzle segment assembly 30 may support axial loadingas may be gleaned from the depicted schematic connections. A rotor 23may be located radially inward of the nozzle segment assembly 30.

The embodiment also depicts the transfer of axial load from the nozzlevane 50 through the inner support ring 40 and the outer support ring 60.Near lower and upper ends of the nozzle faring 50 are studs 51, 53. Atthe inner and outer support rings 40, 60, the studs 51, 53 arepositioned to engage and allow transfer of axial load. In the depiction,the axial load transfer may be generally in a left-right direction dueto the purely radial engagement of surfaces such as at the outer supportring 60 with stud 53. Additionally, or alternatively, the axial loadtransfer may also be angled slightly relative to the axial direction, asshown by the angled engaging surfaces of the studs 51, 53 and walls orflanges of the inner support ring 40.

Referring still to FIG. 5, the section view also depicts section line9-9 which is shown in FIG. 9. Further, the section view depicts sectionline 10-10 which is shown in FIG. 10. These sections are taken throughthe nozzle segment assembly 30 for viewing at an angle to the radialdirection and in a radial direction, respectively and will be discussedfurther herein.

Referring now to FIG. 6, a partially sectioned perspective view of thenozzle segment assembly 30 is shown. The section view depicts theconstruction and capture of the CMC fairing 50 and metallic strut 70between the outer support ring 60 and the inner support ring 40. Theinstant embodiment utilized is fasteners extending through the outersupport ring 60 and engaging the flange 74 of the strut 70. The seal boxinterface 76 extends into the collar 49 to capture the strut 70 inposition between inner support ring 40 and the outer support ring 60. Asshown in the section view, this also provides a flowpath forcommunication between the cooling flowpath 68 through the strut 70 andinto the cavity 47 to feed the feed holes of the rotor purge feed holes46.

As also shown, the cooling air moving through the struts 70 and coolingpath 68 may pass outwardly through a plurality of cooling holes 79, 86(FIG. 4) which are utilized to cool the vane 56. The vane 56 is at leastpartially hollow to positioning of the strut 70 therein and allows forcooling air to move along the interior of the vane to cooling film holeslocated along the vane.

FIG. 6 also depicts the capturing or sandwiching of the CMC fairing 50at one or more locations between the strut 70 and the seal box or innerring 40. The strut 70 includes a shoulder 77 which engages a protrusion89 extending from the fairing 50. This provides a radially outerboundary. Radially below the shoulder 77, the nozzle fairing 50 may alsobe captured by the inner support ring 40. In this way, the strut 70 andinner support ring 40 capture the nozzle fairing 50 in position. Thiscapturing or sandwiching may be utilized at various locations ofengagement between the strut 70 and the fairing 50 to lock the assemblytogether and/or transfer load from the nozzle fairing 50 to the strut70.

Referring now to FIG. 7, an axial schematic section view is depicted atthe outer position of the nozzle segment assembly 30. The outer supportring 60 or some extension thereof may include a face 65 which extends inan axial direction and faces tangentially. Adjacent to the face 65 is alug 155 which may extend from or connect to the static structure 15, forexample an engine casing, and may have a corresponding lug face 157which is opposite face 65. Since the lug 155 is fixed, it functions asan anti-clocking feature and reacts to tangential load created by thefairing 50 during operation. This allows transfer of tangential loadfrom the nozzle fairing to the outer support ring 60.

The lug 155 may be formed of a plurality of cross-sectional shapes. Asdepicted, the shape is shown generically as a substantially squareshaped cross section. However, other shapes may be used having the lugface 157 which is substantially parallel to the face 65 for engagementduring operation. Alternatively, the lug face 157 may be a formed ofvarying shapes which extend from the static structure 15, or which isconnected to such static structure 15 in order to support the tangentialloading of the fairing nozzle segment assembly 30.

Referring now to FIG. 8, an axial schematic view of an alternativeconnection for the nozzle segment assembly 30 is provided. Whereas theprevious embodiment accommodated tangential loading, the instantembodiment of FIG. 8 provides for either or both of tangential or radialloading. In the instant embodiment, an axial view of the inner supportring 40 is shown. The connection provides a pin 255 extending throughthe inner support ring 40 and extends in a generally axial direction orat an angle to the axial direction. This connection serves at least twopurposes. First, the pin 255 supports radial loading of the innersupport ring 40. Additionally, the pin 255 connection may supporttangential loading of the inner support ring 40, as well. With respectto both embodiments of FIGS. 7 and 8, the strut 70 and connectionsprovide that load may be transfer either above or below the nozzlefairing 50 to either or both of the outer and lower support rings 60,40.

The shape of the pin 255 is shown as circular, however other shapes maybe utilized. Similarly, a receiving aperture within the inner supportring 40 may be some corresponding shape which matches that of the pin255 shape to transmit or support either or both of radial or tangentialloading. Still further, one skilled in the art should realize that theembodiments of FIGS. 7 and 8 may be used in either the inner or outersupport rings 40, 60.

Referring now to FIG. 9, section view of the strut 70 is shown with asection line through the plurality of load bearing pads 80, as shown inFIG. 5. In this view, the load bearing pads 80 are shown engaging theinterior surface of the cooling flowpath 58 of fairing 50. Through theseload bearing pads 80, load on the fairings 50 is transmitted to thestrut 70. Specifically, as the fairing 50 encounters air flow andreceives pressure load in a tangential direction, the fairing 50 is ableto transmit this loading through the load bearing pads 80 to the strut70. Similarly, the loading from the strut 70 may be transmitted to theouter support ring 60 by way of the load pads 75 (FIG. 14) on the flange74 (FIG. 14).

With reference to FIG. 10, a section view is taken of the strut 70 atthe load bearing pad 82, as shown in FIG. 5. According to the sectionview of FIG. 10, the view is shown looking down the strut 70. The innerband 52 is shown for reference as in the previous figure. The loadbearing pad 82 is shown extending from a lower end of the strut 70 so asto engage the lower end of the fairing 50 and more specifically, theinside surface of cooling flowpath 58.

Referring now to FIG. 11, a perspective view of an alternative nozzlesegment assembly 130 is provided with a further embodiment for mountingthe nozzle segment assembly 130. A nozzle fairing 150 includes an innerband 152 and an outer band 154 at radial ends of a vane 156. A strut 170extends into the vane 156 and includes at least one shiplap 172 at anaxial end of the outer band 154. The shiplap 172 is longer in thecircumferential direction than the length of the outer band 154. One endof the shiplap 172 includes a shiplap notch 174 which receives acircumferential end of an adjacent shiplap 172. This notch 174 andshiplap 172 provide a shiplap joint 176. In the instant embodiment, theshiplap joints 176 are located at the aft end of the outer band 154.However, the shiplap joints 176 may alternatively be moved to theforward end of the outer band 154 or an intermediate location. Further,the shiplaps 172 and shiplap joints 176 may additionally, oralternatively, be used along the inner band 152.

At the forward end of the nozzle segment assembly 130 is an L-shapedshoulder 180. The shoulder 180 is defined by a first portion 182extending from the outer band 154 and a second portion 184. Shoulder 180is supported from the static structure 15 (FIG. 5) along with theshiplaps 172. The shoulders 180 and the shiplaps 172 are also connectedto the strut 170 so that the support for each nozzle segment assembly130 is provided by the static structure 15 (FIG. 5) and through thestrut 170.

Referring now to FIG. 12, a perspective view of an exemplary innersupport ring 40 is depicted. The inner support ring 40 may be formed asa single structure or may be formed of two or more pieces or structures.The instant embodiment utilizes a first portion 41 including the lowersurface 42 and radially extending surface 44 and a second portion 45which is inserted into the first portion 41. The second portion 45 maybe press-fit, braised or fastened into the first portion 41. The secondportion 45 may alternatively be formed integrally with the first portion41. The second portion 45 provides a flow cavity for cooling air betweenthe collars 48, 49 and the rotor purge feed holes 46.

Referring now to FIG. 13, a side section view of the inner support ring40 is depicted. In the embodiment, the section cut is made through thecollar 49. The collar 49 is shown as being circular in the depictedembodiment, however alternate shapes may be utilized to receive a lowerseal box interface 76 of the strut 70. Cooling air enters the innersupport ring 40 from the strut 70 and moves in the axially forwarddirection to a cavity 47 which is in flow communication with the rotorpurge feed holes 46.

The collar 49 provides a lower support for capturing the strut 70 andinhibiting circumferential movement of the strut 70 and axial movementof the strut 70. The collar 49 includes a fastening aperture 147 throughwhich a fastener may be positioned and further engage the strut 70 tocapture the strut 70 in position once placed within the collar 49. Thisinhibits radial motion of the strut 70 relative to the inner supportring 40. Radial motion may further be limited by the outer support ring60.

Referring now to FIG. 14, a perspective view of the strut 70 is shown.At the top of the strut 70, the flange 74 is located and includes theplurality of fastening holes 72 which match a pattern provided in theouter support ring 60. With the matching pattern of fastening holes 72,the flange 74 is bolted to the outer support ring 60 providing an upperpositioning limit of the strut 70 while the inner support ring 40provides a lower limit. The flange 74 further comprises the coolingflowpath 78 for cooling air through the nozzle segment assembly 30. Theflange 74 may also comprise a plurality of pads 75 about the peripheraledge to transmit load from the upper band of fairing 50 or to the outersupport ring 60.

Beneath the flange 74 are a plurality of load bearing pads 80 which areprimarily located in a position corresponding to the pressure side ofvane 56 (FIG. 4), although this is merely exemplary and pads may belocated at various locations other than corresponding to the pressureside. During operation, the pressure side of the vane 56 creates a forcewhich pushes the vane 56 and fairing 50 in a circumferential directionof the gas turbine engine 10. The load bearing pads 80 receive thisloading and transmit the loading to the strut 70 so that the fairing 50is not damaged. While two load bearing pads 80 are shown on the pressureside of vane 56, additional load bearing pads 80 may be located forexample in a location corresponding to the leading edge 81 of the vane56 where the high pressure combustion gas engages the vane 56 andfairing 50.

The interior of the strut 70 is at least partially hollow providing toflowpaths 78 therein. According to one flowpath, cooling air may engagethe cooling holes 86 for cooling of the vanes 56. These cooling holes 86may feed film holes located at various locations in the vane 56.According to a second flowpath, the air, shown in broken line, movesdownwardly through the strut 70 and out through the seal box interface76 so as to provide rotor purge air into the seal box cavity 47 (FIG.12) and through the feed holes 46 (FIG. 12).

A load bearing pad 82 is also shown at the lower end of the strut 70which receives loading from the vane 56 as previously described andtransmits the force load to the strut 70 which provides improved loadhandling for the nozzle segment assembly 30.

Along the right-hand side of the strut 70 extending downwardly is a body85 which has a leading edge 81 and a trailing edge 83. The trailing edge83 includes a plurality of cooling holes 79 which cool the trailing edge83 of the vane 56. Accordingly the interior of the strut 70 providesflowpath communication to cooling holes 79 located at the trailing edge83 as well as the seal box interface 76 for cooling of the inner supportring 40. It should be understood that while cooling holes 79 are shownat one location, additional locations of the strut 70 may comprise othersuch cooling holes. Also, the cooling holes 86 may be arranged inalternate patterns and configurations and should be limited to thespecific pattern shown.

As an alternative, or in addition to the fastening holes 72, one or morestuds 73 may extend from the upper surface of the strut 70. The studs 73may locate the strut 70 relative to the outer support ring 60 (FIG. 4)or a static structure 15 (FIG. 5) such as an engine casing or otherfixed structure. The studs 73 may also function to transfer somecircumferential or tangential loading.

Referring now to FIG. 15, a side section view of the strut 70 isdepicted. The flange 74 is shown at the upper end and one of thefastening holes 72 is depicted with a second aperture being cut through.While the interior of the strut 70 is depicted as being substantiallyopen, alternative embodiments may include walls for directing flow ofcooling air to desired locations. As previously mentioned, it is withinthe scope of this disclosure to provide cooling at different locationsof the strut and the depicted embodiment is merely exemplary.

With reference to FIG. 16, an alternative embodiment of a nozzle segmentassembly 130 is shown wherein inner and outer support rings 140, 160extend 360 degrees rather than being formed of segments as in previousembodiments. The nozzle segment assembly 130 includes an outer supportring 160 which captures a strut 170 and a nozzle fairing 150 in positionabove an inner support ring 140. The instant embodiment utilizes innerand outer bands 152, 154 which are curved along the axial direction morethan the previous embodiment. Additionally, the fairing 150 of theinstant segment includes a single vane 156. Thus, it should beunderstood that the nozzle segment assemblies 30, 130 may vary incircumferential length and may vary in axial length and shape dependingupon the components of the gas turbine engine 10 in the area where thenozzle segment assembly will be mounted and depending on designparameters for conditions within the gas turbine engine 10. For example,the nozzle segment assembly 30, 130 may be of preselected segmentedlength or may form a complete ring.

The foregoing description of several embodiments of the invention hasbeen presented for purposes of illustration. It is not intended to beexhaustive or to limit the invention to the precise steps and/or formsdisclosed, and obviously many modifications and variations are possiblein light of the above teaching. It is intended that the scope of theinvention and all equivalents be defined by the claims appended hereto.

The invention claimed is:
 1. A nozzle segment assembly, comprising: anouter support ring and an inner support ring; a nozzle fairing formed ofa low coefficient of thermal expansion material having an outer band, aninner band, and a vane extending between said outer band and said innerband; and a metallic strut extending between said outer support ring andsaid inner support ring, said metallic strut allowing for load transferbetween said nozzle fairing and said metallic strut, wherein saidmetallic strut extends through said nozzle fairing and allows radialgrowth of said metallic strut through said vane, and wherein said outerband of said nozzle fairing is positioned to engage with and transferload to said outer support ring or said inner band of said nozzlefairing is positioned to engage with and transfer load to said innersupport ring.
 2. The nozzle segment assembly of claim 1, wherein saidouter support ring and said inner support ring are 360 degree rings. 3.The nozzle segment assembly of claim 1, wherein said outer support ringand said inner support ring are arcuate segments.
 4. The nozzle segmentassembly of claim 1, wherein at least one of said outer support ring andsaid inner support ring are supported by a static structure.
 5. Thenozzle segment assembly of claim 4, wherein said at least one of saidouter support ring and said inner support ring is supported in acantilevered arrangement from said static structure.
 6. The nozzlesegment assembly of claim 4, wherein at least one of said outer supportring and said inner support ring are supported at an axial end.
 7. Thenozzle segment assembly of claim 1, wherein said metallic strut isconnected to at least one of said inner support ring and said outersupport ring by bolting, fastening, capturing, or being integrallyformed.
 8. The nozzle segment assembly of claim 1, wherein a radialposition of said nozzle fairing is captured between said outer supportring and inner support ring.
 9. The nozzle segment assembly of claim 8,further comprising an interface at a lower end of said metallic strutthat extends into a collar of said inner support ring.
 10. The nozzlesegment assembly of claim 8, further comprising a pin joint at one ofsaid inner support ring and said outer support ring.
 11. The nozzlesegment assembly of claim 1, further comprising a flowpath through saidnozzle segment assembly, wherein said flowpath further comprises atleast one cavity extending through said vane of said nozzle fairing. 12.The nozzle segment assembly of claim 11, wherein said flowpath furthercomprises at least one cavity extending through said metallic strut andin flow communication with said cavity of said nozzle fairing.
 13. Thenozzle segment assembly of claim 12, wherein said metallic strut has aplurality of cooling holes for impingement air on an interior surface ofsaid vane.
 14. The nozzle segment assembly of claim 13, wherein saidvane of said nozzle fairing has a plurality of cooling film holes inflow communication with said flowpath, wherein said flowpath is furtherin flow communication with said inner band.
 15. The nozzle segmentassembly of claim 1, wherein said vane is integrally formed with saidouter band and said inner band.
 16. The nozzle segment assembly of claim15, wherein the nozzle fairing is unattached to the outer support ringand the inner support ring such that the nozzle fairing floats along aradial direction.
 17. The nozzle segment assembly of claim 16, wherein aradial position of said nozzle fairing is captured between said outersupport ring and inner support ring.
 18. The nozzle segment assembly ofclaim 1, wherein the vane is unattached to the outer support ring andthe inner support ring such that the vane floats along a radialdirection.
 19. The nozzle segment assembly of claim 1, wherein saidnozzle fairing has a stud positioned to allow transfer of load from saidnozzle fairing to said outer support ring or said inner support ring.20. The nozzle segment assembly of claim 1, wherein said nozzle fairingmakes direct contact with said inner support ring or said outer supportring.